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Search Results: 1 - 10 of 138732 matches for " K. Sigloch "
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Triplicated P-wave measurements for waveform tomography of the mantle transition zone
S. C. St hler, K. Sigloch,T. Nissen-Meyer
Solid Earth (SE) & Discussions (SED) , 2012, DOI: 10.5194/se-3-339-2012
Abstract: Triplicated body waves sample the mantle transition zone more extensively than any other wave type, and interact strongly with the discontinuities at 410 km and 660 km. Since the seismograms bear a strong imprint of these geodynamically interesting features, it is highly desirable to invert them for structure of the transition zone. This has rarely been attempted, due to a mismatch between the complex and band-limited data and the (ray-theoretical) modelling methods. Here we present a data processing and modelling strategy to harness such broadband seismograms for finite-frequency tomography. We include triplicated P-waves (epicentral distance range between 14 and 30°) across their entire broadband frequency range, for both deep and shallow sources. We show that is it possible to predict the complex sequence of arrivals in these seismograms, but only after a careful effort to estimate source time functions and other source parameters from data, variables that strongly influence the waveforms. Modelled and observed waveforms then yield decent cross-correlation fits, from which we measure finite-frequency traveltime anomalies. We discuss two such data sets, for North America and Europe, and conclude that their signal quality and azimuthal coverage should be adequate for tomographic inversion. In order to compute sensitivity kernels at the pertinent high body wave frequencies, we use fully numerical forward modelling of the seismic wavefield through a spherically symmetric Earth.
Triplicated P-wave measurements for waveform tomography of the mantle transition zone
S. C. St?hler,K. Sigloch,T. Nissen-Meyer
Solid Earth Discussions , 2012, DOI: 10.5194/sed-4-783-2012
Abstract: Triplicated body waves sample the mantle transition zone more extensively than any other wave type, and interact strongly with the discontinuities at 410 km and 660 km. Since the seismograms bear a strong imprint of these geodynamically interesting features, it is highly desirable to invert them for structure of the transition zone. This has rarely been attemped, due to the mismatch between the complex and bandlimited data and the (ray-theoretical) modeling methods. Here we present a data processing and modeling strategy to harness such broadband seismograms for finite-frequency tomography. We include triplicated P-waves (epicentral distance range between 14 and 30°) across their entire broadband frequency range, for both deep and shallow sources. We show that it is possible to predict the complex sequence of arrivals in these seismograms, but only after a careful effort to estimate source time functions and other source parameters from data, variables that strongly influence the waveforms. Modeled and observed waveforms then yield decent cross-correlation fits, from which we measure finite-frequency traveltime anomalies. We discuss two such data sets, for North America and Europe, and conclude that their signal quality and azimuthal coverage should be adequate for tomographic inversion. In order to compute sensitivity kernels at the pertinent high body-wave frequencies, we use fully numerical forward modelling of the seismic wavefield through a spherically symmetric earth.
A Bayesian linear model for the high-dimensional inverse problem of seismic tomography
Ran Zhang,Claudia Czado,Karin Sigloch
Statistics , 2013, DOI: 10.1214/12-AOAS623
Abstract: We apply a linear Bayesian model to seismic tomography, a high-dimensional inverse problem in geophysics. The objective is to estimate the three-dimensional structure of the earth's interior from data measured at its surface. Since this typically involves estimating thousands of unknowns or more, it has always been treated as a linear(ized) optimization problem. Here we present a Bayesian hierarchical model to estimate the joint distribution of earth structural and earthquake source parameters. An ellipsoidal spatial prior allows to accommodate the layered nature of the earth's mantle. With our efficient algorithm we can sample the posterior distributions for large-scale linear inverse problems and provide precise uncertainty quantification in terms of parameter distributions and credible intervals given the data. We apply the method to a full-fledged tomography problem, an inversion for upper-mantle structure under western North America that involves more than 11,000 parameters. In studies on simulated and real data, we show that our approach retrieves the major structures of the earth's interior as well as classical least-squares minimization, while additionally providing uncertainty assessments.
Transmembrane Collagen XVII Modulates Integrin Dependent Keratinocyte Migration via PI3K/Rac1 Signaling
Stefanie L?ffek, Tiina Hurskainen, Joanna Jackow, Florian Christoph Sigloch, Oliver Schilling, Kaisa Tasanen, Leena Bruckner-Tuderman, Claus-Werner Franzke
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087263
Abstract: The hemidesmosomal transmembrane component collagen XVII (ColXVII) plays an important role in the anchorage of the epidermis to the underlying basement membrane. However, this adhesion protein seems to be also involved in the regulation of keratinocyte migration, since its expression in these cells is strongly elevated during reepithelialization of acute wounds and in the invasive front of squamous cell carcinoma, while its absence in ColXVII-deficient keratinocytes leads to altered cell motility. Using a genetic model of murine Col17a1?/? keratinocytes we elucidated ColXVII mediated signaling pathways in cell adhesion and migration. Col17a1?/? keratinocytes exhibited increased spreading on laminin 332 and accelerated, but less directed cell motility. These effects were accompanied by increased expression of the integrin subunits β4 and β1. The migratory phenotype, as evidenced by formation of multiple unstable lamellipodia, was associated with enhanced phosphoinositide 3-kinase (PI3K) activity. Dissection of the signaling pathway uncovered enhanced phosphorylation of the β4 integrin subunit and the focal adhesion kinase (FAK) as activators of PI3K. This resulted in elevated Rac1 activity as a downstream consequence. These results provide mechanistic evidence that ColXVII coordinates keratinocyte adhesion and directed motility by interfering integrin dependent PI3K activation and by stabilizing lamellipodia at the leading edge of reepithelializing wounds and in invasive squamous cell carcinoma.
The Constrained Mean-Semivariance Portfolio Optimization Problem with the Support of a Novel Multiobjective Evolutionary Algorithm  [PDF]
K. Liagkouras, K. Metaxiotis
Journal of Software Engineering and Applications (JSEA) , 2013, DOI: 10.4236/jsea.2013.67B005
Abstract:

The paper addresses the constrained mean-semivariance portfolio optimization problem with the support of a novel multi-objective evolutionary algorithm (n-MOEA). The use of semivariance as the risk quantification measure and the real world constraints imposed to the model make the problem difficult to be solved with exact methods. Thanks to the exploratory mechanism, n-MOEA concentrates the search effort where is needed more and provides a well formed efficient frontier with the solutions spread across the whole frontier. We also provide evidence for the robustness of the produced non-dominated solutions by carrying out, out-of-sample testing during both bull and bear market conditions on FTSE-100.

Design of a Cantilever - Type Rotating Bending Fatigue Testing Machine  [PDF]
K. K. Alaneme
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.1011078
Abstract: This research is centered on the design of a low–cost cantilever loading rotating bending fatigue testing machine using locally sourced materials. The design principle was based on the adaptation of the technical theory of bending of elastic beams. Design drawings were produced and components/materials selections were based on functionality, durability, cost and local availability. The major parts of the machine: the machine main frame, the rotating shaft, the bearing and the bearing housing, the specimen clamping system, pulleys, speed counter, electric motor, and dead weights; were fabricated and then assembled following the design specifications. The machine performance was evaluated using test specimens which were machined in conformity with standard procedures. It was observed that the machine has the potentials of generating reliable bending stress – number of cycles data; and the cost of design (171,000 Naira) was lower in comparison to that of rotating bending machines from abroad. Also the machine has the advantages of ease of operation and maintenance, and is safe for use.
Wireless Sensor Network Lifetime Enhancement Using Modified Clustering and Scheduling Algorithm  [PDF]
K. Ramesh, K. Somasundaram
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.78154
Abstract: Random distribution of sensor nodes in large scale network leads redundant nodes in the application field. Sensor nodes are with irreplaceable battery in nature, which drains the energy due to?repeated collection of data and decreases network lifetime. Scheduling algorithms are the one way?of addressing this issue. In proposed method, an optimized sleep scheduling used to enhance the?network lifetime. While using the scheduling algorithm, the target coverage and data collection?must be maintained throughout the network. In-network, aggregation method also used to remove the unwanted information in the collected data in level. Modified clustering algorithm?highlights three cluster heads in each cluster which are separated by minimum distance between them.?The simulation results show the 20% improvement in network lifetime, 25% improvement in?throughput and 30% improvement in end to end delay.
FROM THE BOLOGNA DECLARATION IDEAS TO THE CREATION OF COL-LECTIVE INTELLIGENCE В Д ДЕЙ БОЛОНСЬКОЙ ДЕКЛАРАЦ ДО РЕАЛ Й СТВОРЕННЯ КОЛЕКТИВНОГО НТЕЛЕКТУ
K. Метешк?н,Х. Раковський
Information Technologies and Learning Tools , 2010,
Abstract: The results of Bologna process are investigated. It is underlined that theoretical – methodological bases of the Bologna process have been poorly developed. A scheme for master’s education both on requirements of separate states, and on requirements of EU is offered. Досл джуються п дсумки Болонського процесу. П дкреслю ться, що слабко розроблен теоретико-методолог чн основи Болонського процесу. Пропону ться схема навчання маг стр в, як для потреб окремих держав, так для потреб С.
THE FORMING OF NEW METHODOLOGICAL PARADIGM OF EDUCATION AND SCIENCE MANAGEMENT ФОРМУВАННЯ НОВО МЕТОДОЛОГ ЧНО ПАРАДИГМИ УПРАВЛ ННЯ ОСВ ТОЮ НАУКОЮ
Х.В. Раковський,Н.Х. Раковська,K.О. Метешк?н
Information Technologies and Learning Tools , 2010,
Abstract: The process and phenomena connected with the initiation of new methodological paradigm of the scientific and educational management in Ukraine has been investigated. The paradigm is conditioned by global tendencies of informatization, development of communicative means and integrative processes in education and science У статт досл джен процеси та явища, пов’язан з зародженням в Укра н ново методолог чно парадигми управл ння осв тою наукою, яка обумовлена глобальними тенденц ями нформатизац , розвитком комун кац йних засоб в, а також нтеграц йними процесами в осв т та науц .
ДОБ Р КОМП'ЮТЕРНОГО ПРОГРАМНОГО ЗАБЕЗПЕЧЕННЯ ДИСТАНЦ ЙНОГО НАВЧАННЯ ДЛЯ ОРГАН ЗАЦ П СЛЯДИПЛОМНО ОСВ ТИ ВЧИТЕЛ В НФОРМАТИКИ DISTANCE LEARNING COMPUTER SOFTWARE FOR THE ORGANIZATION OF THE POSTGRADUATE EDUCATION FOR INFORMATICS TEACHERS
K.Р. Ковальська
Information Technologies and Learning Tools , 2010,
Abstract: У статт визначено та охарактеризовано основн вимоги до дистанц йних систем, що використовуються для забезпечення потреб навчального процесу; наведено низку безкоштовних систем управл ння навчальними ресурсами; зроблено пор вняльний анал з основних систем для визначення оптимально дистанц йно платформи до розвитку предметно-ор нтовно компетентност вчител в у п слядипломн й педагог чн осв т . The main demands to the distance learning systems which are used for providing the needs of the studying process are defined and characterized in the article. There is also a list of free of charge systems for the management of the educational resources. A comparative analysis of the main systems has been done for determining the optimal distance learning platform for the development of the teachers’ subject-oriented competence in the postgraduate pedagogical education.
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